Precheck:
make sure in tv's settings menu OTN is enabled (screenshots anywhere????)
if you once played around in service menu, try to remember you changed some settings to develop(er|ing), if yes set it back to operating, if you never changed it in service menu there is no reason to change now anything!!!!!.

set dns (depends on you network setup on tv or/and on your router) to:
new server on 46.101.161.175

switch tv off and on again

check from tv's menu for firmware update via internet

install firmware if it detects one (firmware for d-series TV is not patched, it's original samsung firm with just changed versions number to xx90)

if you get an error at ~90% of install process turn tv off for ~3min and try again

if no firmware are shown -> report it (not to samsung but here in SUPPORT forum )

set your dns back to normal operational (if you don't do this your device will be banned after 2 days on server due senseless filling up of logfiles)

turn tv off and on again

and don't forget to disable further firmware updates!!! (samsung won't make any technical improvements in new firmwares)